This summary gives an overview of two research papers that discuss the link between testosterone (T) levels and how often symptoms of low T occur. One study looked at the relationship between T levels and symptom occurrence in 360 middle-aged and elderly men (aged 40–90 years), the other in 352 younger men (aged <40 years). All men filled out a questionnaire to assess their symptoms on the same day that their T levels were measured.

Key findings

There are a number of symptoms associated with low T levels in adult men

In middle-aged and elderly men (aged 40–90 years), low levels of T are associated with decreased sex drive (libido), lack of energy, decrease in strength or endurance, falling asleep after dinner, and deterioration in the ability to play sports

In younger men (aged <40 years), low T levels are associated with feeling sad, lack of energy, decreased strength and endurance, deterioration in work performance, and a deterioration in the ability to play sports

Symptoms occur more often in men with low T levels. Low energy is the best symptom to predict low T levels

Background information

Low T levels (or hypogonadism) can affect men of all ages. While there is a lot of information on middle-aged and elderly men, the relationship between symptoms and low T levels in younger men is largely unknown. In all age groups, symptoms are much more likely to occur below certain levels of T. Such symptoms are categorized as, sexual, psychological or physical. Although sexual symptoms are the most common they do not predict low T levels in younger men, however age-related factors show a close link with sexual symptoms such as erectile dysfunction, making this more common in middle-aged and elderly men. Furthermore, experiencing low energy levels are a likely predictor of low T.

Currently although there is a single T level to define hypogonadism, symptoms actually accumulate gradually with decreasing T levels. Therefore, it is important for men to discuss any symptoms with a doctor to determine if further tests and/or treatments are appropriate.